KR20220058699A - Resin composition, adhesive member, and display device including the same - Google Patents

Abstract

The present invention provides a resin composition including an urethane (meth)acrylate oligomer, having a difference of less than 2% between the shear strain ratio 5 seconds after applying a shear strain of 2000 Pa after UV curing and the shear strain ratio 300 seconds after applying a shear strain of 2000 Pa after UV curing, and showing a shear strain ratio of less than 2% 30 seconds after removing the shear strain. The resin composition according to the present invention has low viscosity in a liquid composition state to realize excellent coatability. In addition, the adhesive member formed through the photocuring of the resin composition according to the present invention shows low elastic modulus and high elastic restorability, and thus can provide high reliability when being used in a flexible display device.

Description

A resin composition, an adhesive member, and a display device including the adhesive member {RESIN COMPOSITION, ADHESIVE MEMBER, AND DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a resin composition, an adhesive member formed of the resin composition, and a display device including the adhesive member.

Various display devices used in multimedia devices such as televisions, mobile phones, tablet computers, navigation devices, and game machines have been developed. In particular, in recent years, development of a display device capable of folding, bending, or rolling by providing a flexible display member that can be bent to facilitate portability and improve user convenience is being developed.

In the case of such a flexible display device, it is necessary to secure reliability of each member used in a folding or bending operation. In addition, an adhesive resin used to form an adhesive layer applied to various types of display devices needs to have excellent coating properties on members of various types of display devices.

It is an object of the present invention to provide a resin composition having excellent applicability and having a low storage modulus and high elastic recovery force after curing, and an adhesive member prepared therefrom.

Another object of the present invention is to provide a display device having excellent reliability in an operation state such as folding, including an adhesive member having low elastic modulus and high elastic recovery force characteristics.

The resin composition according to an embodiment of the present invention includes a urethane (meth)acrylate oligomer. When a shear strain of 2000 Pa is applied to the resin composition according to an embodiment of the present invention after UV curing, the difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%, and the shear strain is removed and The shear strain after 30 seconds is less than 2%.

The resin composition according to an embodiment of the present invention may have a viscosity of 20 mPa·s or less at 30° C. or higher and 50° C. or lower as measured by the JIS Z8803 method.

The shear strain after 5 seconds after the load may be less than 20%.

The urethane (meth)acrylate oligomer may be included in an amount of 1 wt% or more and 15 wt% or less based on the total amount of the resin composition.

After curing the resin composition according to an embodiment of the present invention, the storage modulus at 25° C. may be 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less.

After curing the resin composition according to an embodiment of the present invention, the storage modulus at 60° C. may satisfy Equation 1 below with respect to the storage modulus at 25° C.

[Equation 1]

0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0

The urethane (meth)acrylate oligomer may have a molecular weight of 10000 or more.

The resin composition according to an embodiment of the present invention may further include a difunctional (meth)acrylate monomer, and the difunctional (meth)acrylate monomer may be included in an amount of less than 1% by weight based on the total amount of the resin composition.

The resin composition according to an embodiment of the present invention further comprises a phosphate ester-based (meth)acrylate monomer, wherein the phosphate ester-based (meth)acrylate monomer is 1 wt% or more and 10 wt% or less with respect to the total amount of the resin composition can be included as

The resin composition according to an embodiment of the present invention may further include an organic solvent, and the organic solvent may be included in an amount of less than 1% by weight based on the total amount of the resin composition.

The adhesive member according to an embodiment of the present invention includes a urethane (meth)acrylate oligomer, and a polymer derived from a resin composition having a viscosity of 20 mPa·s or less at 30°C or higher and 50°C or lower as measured by the JIS Z8803 method. do. When a shear strain of 2000 Pa is applied to the adhesive member according to an embodiment of the present invention, the difference between the shear strain after 5 seconds after the load and the shear strain after 300 seconds after the load is less than 5%, and 30 seconds after removing the shear strain The shear strain is less than 2%.

A display device according to an exemplary embodiment includes a display panel, a window disposed on the display panel, and an adhesive member disposed between the display panel and the window, wherein the adhesive member includes urethane (meth)acrylate Derived from a resin composition containing an oligomer, and when a shear strain of 2000 Pa is applied to the adhesive member, the difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%, and the shear strain is removed, The shear strain after 30 seconds is less than 2%.

The thickness of the adhesive member may be 50 μm or more and 200 μm or less.

The display device according to an exemplary embodiment may further include an input sensing unit disposed on the display panel, and the adhesive member may be disposed between the display panel and the input sensing unit or between the input sensing unit and the window. can

The display panel may include a display element layer and an encapsulation layer disposed on the display element layer, the input sensing unit may be disposed directly on the encapsulation layer, and the adhesive member may be disposed on the input sensing unit.

The adhesive member may be formed by providing the resin composition directly on one surface of the window or on one surface of the display panel, and UV curing the provided resin composition.

A display device according to an exemplary embodiment may include at least one folding area, and a radius of curvature of the folding area may be 5 mm or less.

The display device according to an embodiment of the present invention further includes a light control layer disposed between the adhesive member and the window, and an optical adhesive layer disposed between the light control layer and the window, wherein the optical adhesive layer includes the resin polymers derived from the composition.

The resin composition of an embodiment may exhibit excellent applicability to substrates of various shapes by having low viscosity characteristics.

The adhesive member according to an embodiment may have a low storage elastic modulus, a small change in storage elastic modulus according to temperature, and a high elastic recovery force when shear deformation is applied.

The display device according to an exemplary embodiment may exhibit excellent reliability in various operating states including an adhesive member having a low storage elastic modulus and a high elastic recovery force.

1 is a perspective view of a display device according to an exemplary embodiment;
FIG. 2 is a diagram illustrating a folded state of the display device shown in FIG. 1 .
3 is a perspective view of a display device according to an exemplary embodiment.
FIG. 4 is a view illustrating a folded state of the display device of FIG. 3 .
5 is a perspective view of a display device according to an exemplary embodiment.
6 is an exploded perspective view of a display device according to an exemplary embodiment;
7 is a cross-sectional view of a display device according to an exemplary embodiment.
8A to 8C are views illustrating a method of manufacturing an adhesive member according to an exemplary embodiment.
9A and 9B are views illustrating a method of manufacturing an adhesive member according to an exemplary embodiment.
10 is a cross-sectional view of a display device according to an exemplary embodiment.
11 is a cross-sectional view of a display device according to an exemplary embodiment.

Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In this specification, when an element (or region, layer, portion, etc.) is referred to as being “on,” “connected to,” or “coupled with” another element, it is directly disposed/on the other element. It means that it can be connected/coupled or a third component can be placed between them.

Meanwhile, in the present application, “directly disposed” may mean that there is no layer, film, region, plate, etc. added between parts of a layer, film, region, plate, etc. and another part. For example, “directly disposed” may mean disposing between two layers or two members without using an additional member such as an adhesive member.

Like reference numerals refer to like elements. In addition, in the drawings, thicknesses, ratios, and dimensions of components are exaggerated for effective description of technical content.

“and/or” includes any combination of one or more that the associated configurations may define.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In addition, terms such as "below", "below", "above", and "upper side" are used to describe the relationship of the components shown in the drawings. The above terms are relative concepts, and are described based on directions indicated in the drawings. In the present specification, "disposed on" may refer to a case of being disposed not only on the upper part of any one member but also on the lower part.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, terms such as terms defined in commonly used dictionaries should be construed as having a meaning consistent with their meaning in the context of the relevant art, and unless they are interpreted in an ideal or overly formal sense, they are explicitly defined herein interpreted as being

Terms such as “comprise” or “have” are intended to designate that a feature, number, step, action, component, part, or combination thereof described in the specification is present, and includes one or more other features, number, or step. , it should be understood that it does not preclude the possibility of the existence or addition of an operation, a component, a part, or a combination thereof.

Hereinafter, a resin composition, an adhesive member, and a display device according to an embodiment will be described with reference to the drawings.

1 is a perspective view of a display device according to an exemplary embodiment; FIG. 2 is a diagram illustrating a folded state of the display device shown in FIG. 1 .

Referring to FIG. 1 , a display device DD according to an exemplary embodiment has long sides extending in a direction of a first direction axis DR1 and extends in a direction of a second direction axis DR2 intersecting the first direction axis DR1 . It may have a rectangular shape having short sides. However, the exemplary embodiment is not limited thereto, and the display device DD may have various shapes such as a circle and a polygon on a plane view. The display device DD may be a flexible display device.

In the display device DD according to an exemplary embodiment, the display surface DS on which the image IM is displayed may be parallel to a surface defined by the first direction axis DR1 and the second direction axis DR2 . The third direction axis DR3 indicates the normal direction of the display surface DS, that is, the thickness direction of the display device DD. The front surface (or upper surface) and the rear surface (or lower surface) of each member are divided by the third direction axis DR3 . However, the directions indicated by the first to third direction axes DR1 , DR2 , and DR3 are relative concepts and may be converted into other directions. Hereinafter, the first to third directions refer to the same reference numerals as directions indicated by the first to third direction axes DR1 , DR2 , and DR3 , respectively.

The display device DD according to an exemplary embodiment may include at least one folding area FA. 1 and 2 , the display device DD may include a folding area FA and a plurality of non-folding areas NFA. The folding area FA is disposed between the non-folding areas NFA, and the folding area FA and the non-folding areas NFA may be arranged adjacent to each other in the first direction axis DR1 direction.

The folding area FA may be a deformable portion in a folded form based on the folding axis FX extending in the second direction axis DR2, which is one direction. A radius of curvature RD of the folding area FA may be 5 mm or less.

1 and 2 , one folding area FA and two non-folding areas NFA are illustrated. However, the number of the folding area FA and the non-folding areas NFA is not limited thereto. does not For example, the display device DD may include more than two non-folding areas NFA and a plurality of folding areas FA disposed between the non-folding areas NFA.

In the display device DD according to an exemplary embodiment, the non-folding areas NFA may be disposed to be symmetrical to each other with respect to the folding area FA. However, the embodiment is not limited thereto, and the folding area FA is disposed between the non-folding areas NFA, and the areas of the two non-folding areas NFA facing each other with respect to the folding area FA are may be different from each other.

The display surface DS of the display device DD may include a display area DA and a non-display area NDA around the display area DA. The display area DA may display an image, and the non-display area NDA may not display an image. The non-display area NDA may surround the display area DA and may define an edge of the display device DD.

Referring to FIG. 2 , the display device DD may be a foldable (foldable) display device DD that can be folded or unfolded. For example, the folding area FA may be bent based on the folding axis FX parallel to the second direction axis DR2 , so that the display device DD may be folded. The folding axis FX may be defined as a short axis parallel to a short side of the display device DD.

When the display device DD is folded, the non-folding areas NFA may face each other, and the display device DD may be in-folded such that the display surface DS is not exposed to the outside. However, the exemplary embodiment is not limited thereto, and unlike the drawings, the display device DD may be out-folded so that the display surface DS is exposed to the outside.

3 is a perspective view of a display device according to an exemplary embodiment. FIG. 4 is a view illustrating a folded state of the display device of FIG. 3 .

Except for the folding operation, the display device DD-a shown in FIG. 3 may have substantially the same configuration as the display device DD shown in FIG. 1 . Accordingly, in the description of the display device DD-a illustrated in FIGS. 3 and 4 , the folding operation will be mainly described below.

3 and 4 , the display device DD-a may include a folding area FA-a and a plurality of non-folding areas NFA-a. The folding area FA-a is disposed between the non-folding areas NFA-a, and the folding area FA-a and the non-folding areas NFA-a are adjacent to each other in the second direction axis DR2 direction. can be arranged.

The folding area FA-a may be bent based on the folding axis FX-a parallel to the first direction axis DR1 , so that the display device DD-a may be folded. The folding axis FX-a may be defined as a long axis parallel to a long side of the display device DD-a. The display device DD shown in FIG. 1 may be folded based on the short axis, whereas the display device DD-a shown in FIG. 3 may be folded based on the long axis. In FIG. 4 , the display device DD-a is illustrated as being in-folded so that the display surface DS is not exposed to the outside, but the embodiment is not limited thereto. It may be folded and out-folded.

5 is a perspective view of a display device according to an exemplary embodiment. The display device DD-b according to an embodiment may include bending areas BA1 and BA2 and a non-bending area NBA, and the bending areas BA1 and BA2 may be bent from one side of the non-bending area NBA. there is.

Referring to FIG. 5 , the display device DD-b according to an exemplary embodiment includes a non-bending area NBA in which an image IM is displayed on the front side, a first bending area BA1 in which an image IM is displayed on the side, and A second bending area BA2 may be included. The first bending area BA1 and the second bending area BA2 may be bent from both sides of the non-bending area NBA, respectively.

Referring to FIG. 5 , in the non-bending area NBA, the image IM is provided in the third direction axis DR3 direction, which is the front surface of the display device DD-b, and the first bending area BA1 is the fifth The second bending area BA2 in the direction of the direction axis DR5 may provide an image in the direction of the fourth direction axis DR4 . The fourth directional axis DR4 and the fifth directional axis DR5 may cross directions with the first to third directional axes DR1 , DR2 , and DR3 . However, the directions indicated by the first to fifth direction axes DR1 to DR5 are relative concepts and are not limited to the direction relationship illustrated in the drawings.

The display device DD-b according to an exemplary embodiment may be a bending display device including a non-bending area NBA and bending areas BA1 and BA2 disposed on both sides of the non-bending area NBA, respectively. Also, although not shown, the display device according to an exemplary embodiment may be a bending display device including one non-bending area and one bending area. In this case, the bending area may be provided by being bent only at one side of the non-bending area.

Although the foldable display device and the bending display device have been illustrated and described with reference to FIGS. 1 to 5 , the embodiment is not limited thereto. The display device according to an exemplary embodiment may be a rollable display device, a flat rigid display device, or a curved rigid display device.

Hereinafter, the description of the display device according to the embodiment will be described with reference to the display device DD that is folded based on the short axis, but the embodiment is not limited thereto. DD-a) and the display device DD-b including the bending region may be applied to various types of display devices.

6 is an exploded perspective view of a display device DD according to an exemplary embodiment. 7 is a cross-sectional view of a display device DD according to an exemplary embodiment. FIG. 7 may be a cross-sectional view of a portion corresponding to line II′ of FIG. 1 .

The display device DD according to an exemplary embodiment may include a display module DM and a window WP disposed on the display module DM. In the display device DD according to an exemplary embodiment, the display module DM may include a display panel DP including a display element layer DP-EL and an input sensing unit TP disposed on the display panel DP. can The display device DD according to an exemplary embodiment may include an adhesive member AP disposed between the display panel DP and the window WP. For example, in the display device DD according to an exemplary embodiment, the adhesive member AP may be disposed between the input sensing unit TP and the window WP. The adhesive member AP may be an optically clear adhesive film (OCA) or an optically clear adhesive resin layer (OCR).

The adhesive member AP may be formed from the resin composition of an exemplary embodiment. The adhesive member AP may include a polymer derived from the resin composition of an exemplary embodiment.

The resin composition of one embodiment includes a urethane (meth)acrylate oligomer. Meanwhile, in the present specification, (meth)acrylate refers to acrylate or methacrylate. The resin composition of an embodiment may include a urethane (meth)acrylate oligomer having a weight average molecular weight (Mw) of 10,000 or more. In the resin composition of one embodiment, the weight average molecular weight of the urethane (meth)acrylate oligomer may be 27,000 or more and 50,000 or less.

In one embodiment, the urethane (meth)acrylate oligomer may include a photocurable compound including at least one (meth)acryloyl group having a urethane bond. The urethane (meth)acrylate oligomer may include at least one of an acrylate having a urethane bond, a urethane acrylate having a polycarbonate skeleton, and a urethane acrylate having a polyether skeleton. For example, the resin composition of one embodiment is a urethane acrylate oligomer UV-3700B (Mitsubishi Chemical Holdings), UN-5500 (Negami Chemical Industrial), UF-C051 (KYOEISHA CHEMICAL), KRM8792 (DAICEL-ALLNEX), and It may include at least one of UN-6305 (Negami Chemical Industrial).

The resin composition including the urethane (meth)acrylate oligomer having a weight average molecular weight of 10,000 or more may exhibit low viscosity properties that can be applied by an inkjet printing method or a dispensing coating method. In addition, the urethane (meth)acrylate oligomer having a weight average molecular weight of 10,000 or more is included in the resin composition as an oligomer having a relatively high degree of polymerization to maintain a high degree of polymerization even after light curing, thereby reducing the storage modulus (G') value and It can exhibit high peel strength characteristics.

The resin composition of one embodiment may include 1 wt% or more and 15 wt% or less of the urethane (meth)acrylate oligomer based on 100 wt% of the total resin composition. The resin composition of one embodiment contains 1 wt% or more and 15 wt% or less of a urethane (meth)acrylate oligomer having a weight average molecular weight of 10,000 or more, and exhibits low viscosity characteristics of 1.0 mPa s or more and 20 mPa s or less in a resin state After light curing, high elastic recovery force is exhibited. Accordingly, when the adhesive member formed of the resin composition according to the exemplary embodiment is applied to the foldable display device, the folding characteristic of the display device may be improved.

The resin composition of an embodiment may further include at least one of a bifunctional (meth)acrylate monomer and a phosphoric acid ester-based (meth)acrylate monomer. The resin composition of an embodiment may further include at least one photoinitiator.

In the resin composition of an embodiment, the bifunctional (meth)acrylate monomer means a (meth)acrylate monomer having two functional groups. Specifically, the bifunctional (meth)acrylate monomer means a (meth)acrylate monomer containing two (meth)acryloyl groups in one molecule. In the resin composition of an embodiment, the difunctional (meth)acrylate monomer may include a plurality of different monomers. For example, in the resin composition of an embodiment, the difunctional (meth)acrylate monomer may include at least one difunctional acrylate monomer and at least one difunctional methacrylate monomer.

The resin composition of an embodiment includes 1,4-butanediol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, and 1,6-hexanediol di (meth) as a difunctional (meth) acrylate monomer. ) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-octanediol diacrylate, 1,12-dodecanediol di (meth) acrylate, neopentyl glycol di (meth) ) acrylate, dicyclopentanyl di (meth) acrylate, cyclohexane-1,4-dimethanol di (meth) acrylate, tricyclodecane dimethanol (meth) diacrylate, dimethylol dicyclopentane di(meth)acrylate, neopentylglycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, or a mixture thereof. there is.

The resin composition of one embodiment may contain less than 1% by weight of a bifunctional (meth)acrylate monomer based on 100% by weight of the total resin composition. The resin composition of one embodiment contains less than 1% by weight of a difunctional (meth)acrylate monomer, and exhibits low viscosity characteristics of 1.0 mPa·s or more and 20 mPa·s or less in a resin state, and exhibits high elastic recovery after light curing. can

In the resin composition of an embodiment, the phosphate ester-based (meth)acrylate monomer is a (meth)acrylate monomer including an ester bond between phosphoric acid and a hydroxyl group, and the resin composition of an embodiment includes a phosphate ester-based (meth)acrylate monomer. Accordingly, a high elastic recovery force of the adhesive member AP formed through the resin composition may be secured, and an optimal storage elastic modulus for the adhesive member AP to be applied to the flexible display device may be secured.

In the resin composition of an embodiment, 2-(methacryloyloxy)ethyl phosphate (SR9050, Satomasa), tris2-(methacryloyloxy)ethyl phosphate] (SR9051, Satomasa) as phosphate ester-based (meth)acrylate monomers ), tris2-(acryloyloxy)ethyl phosphate] (SR9053, Satomasa), 2-hydroxyethyl methacrylate phosphate (KAYAMER PM-2, Nippon Kayaku Co.), or mixtures thereof.

The resin composition of one embodiment may include 1 wt% or more and 10 wt% or less of a phosphoric acid ester-based (meth)acrylate monomer based on 100 wt% of the total resin composition. The resin composition of one embodiment contains 1 wt % or more and 10 wt % or less of a phosphate ester-based (meth) acrylate monomer, and exhibits low viscosity characteristics of 1.0 mPa s or more and 20 mPa s or less in a resin state, and after photocuring It can show high elastic recovery force.

The resin composition of an embodiment may include at least one photoinitiator. In the case of including a plurality of photoinitiators, different photoinitiators may be activated by ultraviolet light of different central wavelengths.

The photoinitiator is 2,2-dimethoxy-1,2-diphenylethan-1-one (2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone) (1-hydroxy-cyclohexyl-phenyl-ketone), 2-hydroxy-2-methyl-1-phenyl-1-propanone (2-hydroxy-2-methyl-1-phenyl-1-propanone), 2-hydroxy Roxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1- propanone), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methylpropa-1-one (2-hydroxy -1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methylpropan-1-one).

In addition, the photoinitiator is 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan- 1-one), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1), 2-Dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (2-dimethylamino-2-(4-methyl-benzyl)- 1- (4-morpholin-4-yl-phenyl) -butan-1-one), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), 2, 4,6-trimethylbenzoyl-diphenyl phosphinate (2,4,6-trimethylbenzoyl-diphenyl phosphinate), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (bis(2,4,6- trimethylbenzoyl)-phenylphosphineoxide), [1-(4-phenylsulfanylbenzoyl)heptylideneamino]benzoate ([1-(4-phenylsulfanylbenzoyl)heptylideneamino]benzoate), [1-[9-ethyl-6-(2) -Methylbenzoyl)carbazol-3-yl]ethylideneamino] acetate ([1-[9-ethyl-6-(2-methylbenzoyl)carbazol-3-yl]ethylideneamino] acetate), and bis(2,4- Cyclopentadienyl)bis[2,6-difluoro-3-(1-pyryl)phenyl]titanium(IV)(Bis(2,4-cyclopentadienyl)bis[2,6-difluoro-3-(1-) It may be any one selected from pyrryl)phenyl]titanium(IV)).

The resin composition of one embodiment may not include a separate organic solvent. Alternatively, the resin composition of one embodiment includes an organic solvent, but the organic solvent may be included in an amount of less than 1% by weight based on 100% by weight of the total resin composition. The resin composition of an embodiment does not contain an organic solvent or contains less than 1 wt% of an organic solvent, thereby improving processability of the resin composition.

Existing resin compositions use polymers to secure the elastic recovery force of the adhesive member formed through the resin composition, but when using polymers, the use of organic solvents is essential. Occurs. The resin composition of one embodiment can form an adhesive member having a high elastic recovery force without the use of a polymer and an organic solvent, so that an adhesive member having excellent processability in the resin composition state and having a low elastic modulus and high elastic recovery force characteristics can be formed. there is.

The resin composition of one embodiment may have a viscosity of 20 mPa·s or less at 30°C or higher and 50°C or lower. The resin composition of an exemplary embodiment may have a viscosity of 1.0 mPa·s or more and 20 mPa·s or less at 30° C. or more and 50° C. or less. For example, the resin composition may have a viscosity at 40° C. of 1.0 mPa·s or more and 20 mPa·s or less. The viscosity of the resin composition was measured by the JIS Z8803 method.

When the viscosity of the resin composition of one embodiment is less than 1.0 mPa·s, the viscosity is low and the flow of the resin composition solution provided for forming the adhesive member occurs, and accordingly, it may be difficult to form a coating film of a uniform thickness using the resin composition. In addition, when the viscosity of the resin composition of one embodiment is more than 20 mPa·s, it may be difficult to discharge the resin composition in an appropriate amount from the application device used to apply the resin composition.

The liquid resin composition is cured by UV irradiation, and after UV curing, it may have a storage modulus value of 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less at 25°C. The liquid resin composition may satisfy Equation 1 below with respect to the storage elastic modulus at 60° C. and the storage elastic modulus at 25° C. after UV curing.

[Equation 1]

0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0

The resin composition after UV curing has a low storage modulus value at 25°C, and the storage modulus at 25°C and the storage modulus at 60°C may have similar values satisfying Equation 1.

In addition, the liquid resin composition is cured by UV irradiation to form a film or thin film, and after UV curing, it may have a 180° peeling force value of 15N/inch or more with respect to the surface of the glass substrate.

The liquid resin composition cured by UV irradiation may have high elastic recovery. In the liquid resin composition cured by UV irradiation, when a shear strain of 2000 Pa is applied after UV curing, the difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%. When a liquid resin composition cured by UV irradiation is subjected to a shear strain of 2000 Pa after UV curing, if the shear strain after 5 seconds after loading is α%, the shear strain after 300 seconds after loading is (α-5)% or more (α+5)% or less. In one embodiment, when a shear strain of 2000 Pa is applied to the liquid resin composition cured by UV irradiation, the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading may be less than 20%. In one embodiment, when a shear strain of 2000 Pa is applied to the liquid resin composition cured by UV irradiation, the shear strain after 5 seconds after loading is 9% or more and 13% or less, and the shear strain after 300 seconds after loading is 4% may be greater than 18% or less. In addition, after applying a shear strain of 2000 Pa to the cured resin composition according to an embodiment, the shear strain 30 seconds after removing the shear strain is less than 2%. After applying a shear strain of 2000 Pa to the cured resin composition according to an embodiment, the shear strain 30 seconds after removing the shear strain may be less than 0.2%.

The display panel DP includes a base substrate BS, a circuit layer DP-CL disposed on the base substrate BS, a display element layer DP-EL disposed on the circuit layer DP-CL, and An encapsulation layer TFE covering the display element layer DP-EL may be included. For example, the display panel DP may include a plurality of organic light emitting devices or a plurality of quantum dot light emitting devices in the display device layer DP-EL.

Meanwhile, the configuration of the display panel DP shown in FIG. 7 and the like is exemplary and the configuration of the display panel DP is not limited to that shown in FIG. 7 or the like. For example, the display panel DP may include a liquid crystal display, and in this case, the encapsulation layer TFE may be omitted.

The input sensing unit TP may be disposed on the display panel DP. For example, the input sensing unit TP may be directly disposed on the encapsulation layer TFE of the display panel DP. The input sensing unit TP may sense an external input, change it into a predetermined input signal, and provide the input signal to the display panel DP. For example, in the display device DD according to an exemplary embodiment, the input sensing unit TP may be a touch sensing unit sensing a touch. The input sensing unit TP may recognize a direct touch of a user, an indirect touch of a user, a direct touch of an object, or an indirect touch of an object. Meanwhile, the input sensing unit TP may sense at least one of a position of an externally applied touch and an intensity (pressure) of the touch. The input sensing unit TP according to an embodiment of the present invention may have various structures or may be made of various materials, and is not limited to any one embodiment. The input sensing unit TP may include a plurality of sensing electrodes (not shown) for sensing an external input. The sensing electrodes (not shown) may sense an external input in a capacitive manner. The display panel DP may receive an input signal from the input sensing unit TP and generate an image corresponding to the input signal.

The window WP may protect the display panel DP, the input sensing unit TP, and the like. The image IM generated by the display panel DP may be provided to the user through the window WP. The window WP may provide a touch surface of the display device DD. In the display device DD including the folding area FA, the window WP may be a flexible window.

The window WP may include a base layer BL and a printed layer BM. The window WP may include a transmission area TA and a bezel area BZA. The front surface of the window WP including the transmission area TA and the bezel area BZA corresponds to the front surface of the display device DD.

The transmission area TA may be an optically transparent area. The bezel area BZA may be an area having relatively low light transmittance compared to the transmission area TA. The bezel area BZA may have a predetermined color. The bezel area BZA may be adjacent to the transmission area TA and may surround the transmission area TA. The bezel area BZA may define a shape of the transmission area TA. However, the exemplary embodiment is not limited thereto, and the bezel area BZA may be disposed adjacent to only one side of the transmission area TA, or a portion may be omitted.

The base layer BL may be a glass or plastic substrate. For example, a tempered glass substrate may be used as the base layer BL. Alternatively, the base layer BL may be formed of a flexible polymer resin. For example, the base layer BL may include polyimide, polyacrylate, polymethylmethacrylate, polycarbonate, polyethylenenaphthalate, polyvinylidene chloride ( polyvinylidene chloride), polyvinylidene difluoride, polystyrene, ethylene-vinylalcohol copolymer, or a combination thereof. However, the embodiment is not limited thereto, and a general shape known as the base layer BL of the window WP in the related art may be used without limitation.

The printed layer BM may be disposed on one surface of the base layer BL. In an exemplary embodiment, the printed layer BM may be provided on a lower surface of the base layer BL adjacent to the display module DM. The printed layer BM may be disposed on an edge region of the base layer BL. The printing layer BM may be an ink printing layer. In addition, the printed layer BM may be a layer formed including a pigment or a dye. In the window WP, the bezel area BZA may be a portion on which the printed layer BM is provided.

Meanwhile, the window WP may further include at least one functional layer (not shown) provided on the base layer BL. For example, the functional layer (not shown) may be a hard coating layer, an anti-fingerprint coating layer, or the like, but the embodiment is not limited thereto.

There may be a level difference between the portion provided with the printed layer BM and the base layer BL not provided with the printed layer BM. The adhesive member AP of an embodiment formed from the resin composition of the embodiment described above has a low storage modulus and a high adhesive strength value, so that it can be attached to the window WP without lifting at the step portion.

The adhesive member AP according to an embodiment may include a polymer derived from the resin composition of the embodiment described above. That is, the adhesive member AP according to an exemplary embodiment may include a polymer derived from a resin composition including a urethane (meth)acrylate oligomer having a weight average molecular weight of 10,000 or more. The adhesive member (AP) of an embodiment includes a urethane (meth)acrylate oligomer, at least one of a bifunctional (meth)acrylate monomer, and a phosphate ester-based (meth)acrylate monomer, and a photoinitiator. It may include a polymer derived from the resin composition. With respect to the urethane (meth)acrylate oligomer, the bifunctional (meth)acrylate monomer, the phosphate ester-based (meth)acrylate monomer, and the photoinitiator, the same contents as those described in the resin composition of the above-described embodiment may be applied.

The resin composition before the polymerization reaction by the photoinitiator may have a viscosity of 1.0 mPa·s or more and 20 mPa·s or less at 30°C or higher and 50°C or lower measured by the JIS Z8803 method. In addition, the storage elastic modulus of the adhesive member (AP) of an embodiment is 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less at 25°C, and the storage elastic modulus at 60°C can satisfy the following Equation 1 with respect to the storage elastic modulus at 25°C there is.

[Equation 1]

0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0

The adhesive member AP according to an exemplary embodiment may have a low storage modulus at 25°C, and a storage modulus at 25°C and a storage modulus at 60°C may have similar values satisfying Equation 1.

Meanwhile, the 180° peeling force of the adhesive member AP with respect to the glass substrate may be 15N/inch or more.

The adhesive member AP according to an exemplary embodiment may have high elastic recovery force. When a shear strain of 2000 Pa is applied to the adhesive member AP according to an embodiment, the difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%. That is, when a shear strain of 2000 Pa is applied to the adhesive member AP, if the shear strain 5 seconds after loading is α%, the shear strain 300 seconds after loading is (α-5)% or more (α+5)% may be below. In an embodiment, when a shear strain of 2000 Pa is applied to the adhesive member AP, the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading may be less than 20%. When a shear strain of 2000 Pa is applied to the adhesive member AP according to an embodiment, the shear strain after 5 seconds after loading is 9% or more and 13% or less, and the shear strain after 300 seconds after loading is more than 4% and less than 18% there is. In addition, after applying a shear strain of 2000 Pa to the adhesive member AP according to an embodiment, the shear strain 30 seconds after removing the shear strain is less than 2%. After applying a shear strain of 2000 Pa to the adhesive member AP according to an embodiment, the shear strain 30 seconds after removing the shear strain may be less than 0.2%.

The adhesive member AP included in the display device DD according to an embodiment is provided on one surface of the window WP or one surface of the display module DM in a liquid resin composition state, and the window WP and the display module ( DM) may be formed by UV curing the liquid resin composition provided between them. On the other hand, in a separate process, the liquid resin composition is UV-cured to form an adhesive member (AP), and one side of the adhesive member (AP) in a cured state in the form of an adhesive film is applied to one side of the window (WP) or a display module. The adhesive member AP is formed by lamination on one side of the DM and attaching one side of the window WP or one side of the display module DM that is not attached to the other side of the adhesive member AP. can be provided.

The thickness of the adhesive member AP may be 50 μm or more and 200 μm or less. For example, the adhesive member AP may have a thickness of 100 μm or more and 150 μm or less.

8A to 8C are diagrams schematically illustrating steps of manufacturing the adhesive member AP according to an exemplary embodiment. Figure 8a shows the step of providing the resin composition (RC) for forming the adhesive member (AP), Figure 8b shows the step of irradiating ultraviolet light, Figure 8c shows the step of removing the carrier film (CF) it has been shown

8A to 8C , the resin composition RC according to an exemplary embodiment may be provided on the carrier film CF. As the carrier film (CF), for example, a polyethylene terephthalate (PET) film may be used, but the embodiment is not limited thereto. The carrier film CF serves as a base material for coating the liquid resin composition RC, and may be used without limitation as long as it can be easily detached from the adhesive member AP after UV curing. For example, one surface of the carrier film CF on which the resin composition RC is provided may be subjected to a release treatment.

The resin composition RC may be provided by an inkjet printing method, a dispensing method, or the like. The resin composition (RC) of one embodiment can be easily discharged from the nozzle (NZ) by having a viscosity value of 1.0 mPa·s or more and 20 mPa·s or less at 30°C or more and 50°C or less, and a constant coating thickness is maintained may be provided. Specifically, the resin composition (RC) of an embodiment may have a viscosity value of 1.0 mPa·s or more and 20 mPa·s or less at 40°C.

Ultraviolet light (UV) may be irradiated to the pre-adhesive member (P-AP) provided by coating the resin composition (RC) to a predetermined thickness. In FIG. 8B , it is illustrated that ultraviolet light (UV) is directly irradiated to the coated pre-adhesive member (P-AP), but the embodiment is not limited thereto. An auxiliary carrier film (not shown) may be further disposed on the pre-adhesive member (P-AP), and the auxiliary carrier film (not shown) transmits UV light. During the UV curing process, the auxiliary carrier film (P-AP) is removed. It could be to cover.

After UV curing, the adhesive member AP may be formed. The adhesive member (AP) finally provided by removing the carrier film (CF) used during the process has a storage modulus value of 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less at 25°C, and the storage modulus at 60°C is 25°C Equation 1 below may be satisfied for the storage modulus in

[Equation 1]

0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0

The adhesive member AP according to an exemplary embodiment may have a low storage modulus at 25°C, and a storage modulus at 25°C and a storage modulus at 60°C may have similar values satisfying Equation 1.

The adhesive member AP manufactured in the steps of FIGS. 8A to 8C may be applied to the above-described display device DD. For example, one surface of the adhesive member AP is attached to the display module DM, and then on the other surface of the adhesive member AP facing the one surface of the adhesive member AP attached to the display module DM. The windows WP may be sequentially attached. In addition, unlike this, one surface of the adhesive member AP is attached to one surface of the window WP to face the display module DM, and thereafter, the adhesive facing the one surface of the adhesive member AP attached to the window WP. The adhesive member AP may be provided to the display device DD by attaching the other surface of the member AP to the display module DM.

Meanwhile, the resin composition provided between the display module DM and the window WP in liquid form may be cured to form the adhesive member AP. 9A and 9B illustrate manufacturing steps of the adhesive member AP included in the display device DD, manufactured by a method different from the method of manufacturing the adhesive member AP described with reference to FIGS. 8A to 8C .

9A illustrates a step of providing the resin composition RC on the display module DM. In addition, FIG. 9b shows the step of irradiating ultraviolet light to the pre-adhesive member (P-AP) formed from the resin composition (RC).

The resin composition RC may be provided by a method such as an inkjet printing method or a dispensing method. The resin composition (RC) of one embodiment has a viscosity value of 1.0 mPa·s or more and 20 mPa·s or less at 25° C., so that it can be easily discharged from the nozzle (NZ), etc., and provided to maintain a thin and constant coating thickness can be In addition, the resin composition may have a viscosity value of 1.0 mPa·s or more and 20 mPa·s or less to cover the curvature of the step portion SP-a of the display module DM. That is, by having a low viscosity value of 20 mPa·s or less, the resin composition RC may be filled without an empty space in a curved portion such as the step portion SP-a. In addition, since the resin composition RC provided through the nozzle NZ has a viscosity value of 1.0 mPa·s or more, it may be uniformly coated to a predetermined thickness without flowing out of the display module DM.

The window WP may be provided on the preliminary adhesive member P-AP provided by coating the resin composition RC to a predetermined thickness. Ultraviolet light (UV) for curing the resin composition RC may be provided through the window WP. When the window WP is provided on the preliminary adhesive member P-AP, the resin composition RC may be filled without an empty space in the step portion SP-b. That is, since the resin composition (RC) has a low viscosity value of 20 mPa·s or less, the shape of the curvature in the curved portion, such as the step (SP-a) between the base layer (BL) and the printed layer (BM), is reduced. A preliminary adhesive member (P-AP) may be provided while covering. The pre-adhesive member P-AP may be cured after polymerization by UV light provided to form the adhesive member AP.

On the other hand, unlike shown in FIG. 9B and the like, ultraviolet light (UV) is provided to the pre-adhesive member P-AP before the window WP is provided on the pre-adhesive member P-AP to obtain the resin composition RC. The polymerization reaction may proceed. The amount of irradiated ultraviolet light (UV) may be sufficient to completely cure the resin composition (RC). However, unlike this, the polymerization reaction of the resin composition (RC) is partially carried out in the state of the pre-adhesive member (P-AP), and then the unreacted resin composition (RC) is additionally reacted after covering the window (WP) to obtain a final result. An adhesive member AP may be formed.

The display devices DD, DD-a, and DD-b according to the exemplary embodiment shown in FIGS. 1 to 5 include an adhesive member AP including a polymer derived from the above-described exemplary resin composition, Even in the folded state or the bending area, the adhesive state between the window WP and the display module DM may be maintained by using the adhesive member AP without lifting of the adhesive member AP.

10 is a cross-sectional view illustrating a display device according to an exemplary embodiment. Hereinafter, in the description of the display device according to the exemplary embodiment shown in FIG. 10 , content overlapping with the content described with reference to FIGS. 1 to 9B will not be described again, and differences will be mainly described.

Compared to the display device DD described with reference to FIGS. 6 and 7 , the display device DD-1 illustrated in FIG. 10 further includes a light control layer PP and an optical adhesive layer AP-a. may be doing In the display device DD-1 according to the exemplary embodiment, a light control layer PP disposed between the adhesive member AP and the window WP, and an optical adhesive layer disposed between the light control layer PP and the window WP (AP-a) may be further included.

The light control layer PP may be disposed on the display panel DP to control light reflected from the display panel DP by external light. The light control layer PP may include, for example, a polarizing layer or a color filter layer.

The optical adhesive layer AP-a may be an optically clear adhesive film (OCA) or an optically clear adhesive resin layer (OCR). The optical adhesive layer AP-a may be formed from the resin composition of the embodiment in the same manner as the adhesive member AP of the embodiment described above ( FIG. 7 ). That is, the optical adhesive layer (AP-a) is a (meth) acryl monomer containing at least one (meth) acryloyl group, a urethane (meth) acrylate oligomer having a weight average molecular weight of 27,000 or more and 50,000 or less, and at least one It may include a polymer derived from a resin composition including a photoinitiator.

The resin composition before the reaction with the photoinitiator may have a viscosity of 1.0 mPa·s or more and 20 mPa·s or less at 30° C. or more and 50° C. or less as measured by the JIS Z8803 method. In addition, the storage elastic modulus of the optical adhesive layer (AP-a) of an embodiment is 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less at 25°C, and the storage elastic modulus at 60°C is the storage elastic modulus at 25°C. can be satisfied

[Equation 1]

0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0

The optical adhesive layer AP-a according to an embodiment may have a low storage modulus value at 25°C, and a storage modulus at 25°C and a storage modulus at 60°C may have similar values satisfying Equation 1.

The optical adhesive layer AP-a according to an exemplary embodiment may exhibit high elastic recovery force. That is, when a shear strain of 2000 Pa is applied to the optical adhesive layer (AP-a) of an embodiment, the difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%. When a shear strain of 2000 Pa is applied to the optical adhesive layer (AP-a), if the shear strain 5 seconds after loading is α %, the shear strain 300 seconds after loading is (α-5)% or more (α+5)% may be below. In an embodiment, when a shear strain of 2000 Pa is applied to the optical adhesive layer AP-a, the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading may be less than 20%. In one embodiment, when a shear strain of 2000 Pa is applied to the optical adhesive layer (AP-a), the shear strain after 5 seconds after loading is 9% or more and 13% or less, and the shear strain after 300 seconds after loading is more than 4% and 18% may be less than In addition, after applying a shear strain of 2000 Pa to the optical adhesive layer (AP-a) according to an embodiment, the shear strain 30 seconds after removing the shear strain is less than 2%. After applying a shear strain of 2000 Pa to the optical adhesive layer AP-a according to an embodiment, the shear strain 30 seconds after removing the shear strain may be less than 0.2%.

The display device DD-1 according to the embodiment includes an optical adhesive layer AP-a and an adhesive member AP formed from the resin composition of the embodiment, wherein the optical adhesive layer AP-a and the adhesive member AP have a low By exhibiting a storage modulus value and having a high elastic recovery force, a lifting phenomenon does not occur at the interface between the optical adhesive layer AP-a and the adhesive member AP even when the display device DD-1 is folded or bent. Reliability characteristics can be shown.

11 is a cross-sectional view illustrating a display device according to an exemplary embodiment. Hereinafter, in the description of the display device according to the exemplary embodiment shown in FIG. 11 , the content overlapping with the content described with reference to FIGS. 1 to 10 will not be described again, and differences will be mainly described.

Compared to the display device DD described with reference to FIGS. 6 and 7 , the display device DD-2 according to the exemplary embodiment illustrated in FIG. 11 has a light control layer PP, an optical adhesive layer AP-a, and an interlayer structure. It may further include an adhesive layer (PIB). The display device DD-2 according to the exemplary embodiment includes a light control layer PP disposed between the adhesive member AP and the window WP, like the display device DD-1 according to the exemplary embodiment shown in FIG. 10 , and It may further include an optical adhesive layer AP-a disposed between the light control layer PP and the window WP.

In the display device DD - 2 according to an exemplary embodiment, the adhesive member AP may be provided between the display panel DP and the input sensing unit TP. That is, the display panel DP and the input sensing unit TP may be coupled to each other by the adhesive member AP instead of the input sensing unit TP being directly disposed on the display panel DP. For example, the adhesive member AP may be disposed between the encapsulation layer TFE ( FIG. 7 ) of the display panel DP and the input sensing unit TP.

An interlayer adhesive layer PIB may be provided under the light control layer PP. The interlayer adhesive layer PIB is disposed between the input sensing unit TP and the light control layer PP and may be formed of an adhesive material having excellent moisture permeability prevention properties. For example, the interlayer adhesive layer PIB may be formed including polyisobutylene. The interlayer adhesive layer PIB may be disposed on the input sensing unit TP to prevent corrosion of sensing electrodes of the input sensing unit TP.

The display device DD-2 of the exemplary embodiment includes an optical adhesive layer AP-a and an adhesive member AP formed from the resin composition of the exemplary embodiment, and the optical adhesive layer AP-a and the adhesive member AP have a low By exhibiting a storage elastic modulus value and high elastic recovery force, no lifting phenomenon occurs at the interface between the optical adhesive layer AP-a and the adhesive member AP even when the display device DD-2 is folded or bent, resulting in excellent reliability characteristics can indicate

Hereinafter, a resin composition according to an embodiment of the present invention, an adhesive member, and a display device according to an embodiment will be described in detail with reference to Examples and Comparative Examples. In addition, the examples shown below are examples for helping understanding of the present invention, and the scope of the present invention is not limited thereto.

[Example]

One. Curable liquid resin composition preparation

The resin composition of the Example was prepared according to the compounding ratio shown in Table 1. The resin composition of the comparative example was prepared according to the compounding ratio of Table 1. After providing the constituent materials of Examples and Comparative Examples to a heat-resistant light-shielding container in the weight ratios shown in Tables 1 and 2, Omnirad TPO-H (2,4,6-trimethylbenzoyl-diphenylphosphine oxide (2,4,6-trimethylbenzoyl-diphenylphosphine oxide (2) ,4,6-trimethylbenzoyl-diphenylphosphine oxide) was provided in an amount of 2% by weight based on 100% by weight of the total resin composition.Then, the provided materials were used at room temperature using a three-one motor (Shinto Science Co., Ltd.) at 100RPM for 1 hour. It stirred to prepare a curable liquid resin composition.

material Example 1 Example 2 Example 3 Example 4 Example 5 UV-3700B 5.3 5.3 5.2 5.1 5.1 Viscoat #195 0.3 0.9 Viscoat #260 0.4 0.5 SR9050 2.5 4-HBA 2.4 2.4 2.4 2.4 2.4 SYA-4 41 41 41 41 46 IDAA 51 51 51 51 44

material Comparative Example 1 Comparative Example 2 UV-3700B 5 5 8BR-950HB 2.5 4-HBA 22.5 55 SYA-4 IDAA 70 40

<Data on materials used as components of Examples and Comparative Examples>

Data for each component used in Examples and Comparative Examples disclosed in Tables 1 and 2 are as follows.

UV-3700B: Urethane acrylate manufactured by Mitsubishi Chemical Co., Ltd.

Viscoat #195: 1,4-butanediol diacrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.

Viscoat#260: 1,9-nonanediol diacrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.

SR9050: 2-(methacryroyloxy)ethyl phosphate manufactured by Arkema

4-HBA: 4-hydroxybutyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.

SYA004: 10-Hydroxydecyl Acrylate from Sanyu Chemical Research Institute Co., Ltd.

IDAA: Osaka Organic Chemical Co., Ltd. product isodecyl acrylate

8BR-950HB: Multifunctional acrylic polymer manufactured by Daisei Fine Chemicals Co., Ltd.

2. Evaluation of physical properties of the resin composition and the adhesive member formed from the resin composition

In Table 3 below, the viscosity of the resin composition having the composition ratio of Tables 1 and 2, and the storage modulus and flexural reliability of the adhesive member formed from the resin composition were measured and shown. The viscosity of the resin composition, the storage modulus of the adhesive member, and the flexural reliability were measured by the following method.

[Method for measuring viscosity]

The viscosity of the resin composition described in this specification was measured at 40° C. using the JIS Z8803 method, and was measured at a speed condition of 10 rpm using a viscometer TVE-25L (TOKI Corporation).

[Production of storage modulus measurement specimen]

On a slide glass (Slide Glass S1112 manufactured by Matsunami Glass), a PET film (NP100A 100 μm thick, manufactured by Panax) and silicone rubber (0.5 mm thick) with a hole in the diameter of 8 mm are laminated in this order, and 29 μL of After the curable liquid resin composition was dripped, the UV LED lamp which has a peak at 365 nm was used for the slide glass, and the ultraviolet-ray was irradiated so that it might become an accumulated light amount of 150 mJ/cm< ² >. After that, PET film (NP100A 100 μm thick, manufactured by Panax) and slide glass (Slide glass S1112 manufactured by Matsunami Glass) were laminated in this order, and 4000 mJ/cm ² with a metal halide lamp (conveyor-type UV irradiation device manufactured by Eye Graphics) The resin composition was cured by irradiating ultraviolet rays so that the amount of accumulated light was obtained, and a sample having a diameter of 8 mm was obtained.

[Measurement of storage modulus]

The storage modulus of the sample obtained above was measured under the following conditions using a rotary rheometer (MCR302 manufactured by Anton-Paar).

Probe: 8mm diameter flat plate

Normal Force: 1N

Measuring temperature: 25℃

Shear strain: After applying a shear strain of 2000 Pa for 300 seconds, release the shear strain and leave it for 300 seconds

After the shear strain loading, 5 s, after 300 s, and after 30 s after the shear strain was released, the strain rates were recorded, respectively.

[Creation of bending reliability test piece]

0.6 mL of the curable liquid resin composition mix|blended on the PET film (A4100 100 micrometers made by Toyobo Corporation) was dripped, and it spread evenly using the wire bar of #150. The PET film to which the curable liquid resin composition was applied was irradiated with ultraviolet rays so that the amount of accumulated light was 150 mJ/cm 2 using a UV LED lamp having a peak at 365 nm. The PET film irradiated with ultraviolet rays and another PET film (A4100 100 µm manufactured by Toyobo Corporation) were bonded together using a 2 kg hand roller. In the bonded state, the resin composition is cured by irradiating UV rays so that the accumulated light amount is 4000 mJ/cm ² with a metal halide lamp (conveyor-type UV irradiation device manufactured by Eye Graphics) from the side of the bonded PET film, and the sample is 50 mm wide, A sample was obtained by cutting it to a length of 200 mm.

[Bending Reliability Test Method]

The sample obtained above was repeatedly bent 30,000 times at 23° C. and a bending diameter of 3 mm using a durability tester (No-load U-shaped stretch tester manufactured by Yuasa Systems Co., Ltd.). After the end of the test, the presence or absence of occurrence of peeling, floating, shifting, or buckling of the test piece was visually observed, and those without peeling, floating, shifting, or buckling were passed, and those that occurred were regarded as failing.

evaluation item Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Viscosity (mPa s) 14 14 14 14 15 16 12 Deformation (%) after 5 seconds 10 9.5 9.96 9.2 12.6 7.39 4.54 Deformation (%) after 300 seconds 10.9 10.2 10.8 10 13.7 14.5 15.2 Deformation difference (%) 0.9 0.7 0.84 0.8 1.1 7.11 10.66 Deformation after unloading (%) 0.05 0.04 0 0.01 0.14 2.08 5.7 25℃ storage modulus (MPa) 0.033 0.058 0.038 0.042 0.036 0.031 0.079 60℃ storage modulus (MPa) 0.02 0.038 0.027 0.03 0.023 0.01 0.0228 25℃ storage modulus/60℃ storage modulus 1.7 1.5 1.4 1.4 1.6 3.1 3.5 Bend Reliability pass pass pass pass pass fail fail

Referring to the results of Table 3, it can be confirmed that Examples 1 to 5 have a low viscosity of 20 mPa·s or less in the state of the resin composition. The resin compositions of Examples 1 to 5 may be used to form a thin, uniform coating film because they have low viscosity properties. In addition, in Examples 1 to 5, urethane (meth)acrylate having a molecular weight of 10,000 or more The oligomer was used in an amount of 1 wt% or more and 15 wt% or less, and less than 1 wt% of a difunctional (meth)acrylate monomer was used with respect to the total amount of the resin composition, or 1 wt% or more and 10 wt% or less of the total amount of the resin composition. A phosphoric acid ester-based (meth)acrylate monomer was used. In Examples 1 to 5, the resin composition including the above material combination had similar storage modulus values at 25° C. and 60° C. even after light curing, and when a shear strain of 2000 Pa was applied, the shear strain and load after 5 seconds after loading The difference in shear strain after 300 seconds may have a small value of less than 5%. That is, the resin compositions of Examples 1 to 5 may have a small difference in storage elastic modulus for each temperature and high elastic recovery force. Through this, in the resin composition of the embodiment, defects such as peeling, lifting, misalignment, and buckling may not occur in the bending reliability test.

In the case of Comparative Examples 1 and 2, compared to the resin composition of Examples, the bifunctional (meth) acrylate monomer or phosphate ester-based (meth) acrylate monomer was not included, and the shear strain rate after 5 seconds after loading the resin composition of Examples and that the difference in shear strain after 300 seconds after loading is as high as 7% or more, the strain after removing the shear strain is also high at more than 2%, and the storage modulus at 25°C and the storage modulus at 60°C are as high as 3 or more. can be checked As a result, it can be confirmed that, in the resin composition of the comparative example, defects such as peeling, lifting, shifting, and buckling occurred in the flexural reliability test, and thus the resin composition was rejected.

The resin composition of one embodiment has advantageous properties for forming a thin, uniform coating film having a viscosity of 1.0 mPa·s or more and 20 mPa·s or less before curing, and excellent coating properties even on curved surfaces due to low viscosity characteristics. there is. In addition, the adhesive member of one embodiment formed from the resin composition of one embodiment has similar storage modulus values in the range of room temperature (25° C.) and high temperature (60° C.), the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading has a small value of less than 5%, and the shear strain after load removal has a small value of 2% or less. Through this, the display device of the exemplary embodiment exhibits good reliability because there is no peeling or lifting of the adhesive member in the curved portion including the adhesive member formed through the resin composition of the exemplary embodiment, and is adjacent to the adhesive member even in the bending or folding operation state. Since the peeling phenomenon between the members does not occur, excellent operation reliability can be exhibited.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art or those having ordinary knowledge in the technical field do not depart from the spirit and scope of the present invention described in the claims to be described later. It will be understood that various modifications and variations of the present invention may be made within the scope thereof.

Accordingly, the technical scope of the present invention should not be limited to the content described in the detailed description of the specification, but should be defined by the claims.

DD, DD-a, DD-b, DD-1: display device
RC: resin composition AP: adhesive member

Claims (20)

Contains a urethane (meth) acrylate oligomer,
When a shear strain of 2000 Pa was applied after UV curing,
The difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%,
A resin composition having a shear strain of less than 2% after 30 seconds of removing the shear strain. According to claim 1,
The said resin composition is the resin composition whose viscosity in 30 degreeC or more and 50 degrees C or less measured by JIS Z8803 method is 20 mPa*s or less. According to claim 1,
After 5 seconds after the load, the shear strain is less than 20% of the resin composition. According to claim 1,
The urethane (meth) acrylate oligomer is a resin composition comprising 1 wt% or more and 15 wt% or less with respect to the total amount of the resin composition. According to claim 1,
The storage elastic modulus at 25° C. after curing of the resin composition is 1.0X10 ⁴ Pa or more and 1.0X10 ⁵ Pa or less. 6. The method of claim 5,
After curing the resin composition, the storage modulus at 60° C. is a resin composition satisfying the following formula 1 for the storage modulus at 25° C.:
[Equation 1]
0.9 ≤ 25℃ storage modulus/60℃ storage modulus ≤ 2.0 . According to claim 1,
The urethane (meth) acrylate oligomer is a resin composition having a molecular weight of 10000 or more. According to claim 1,
The resin composition further includes a difunctional (meth)acrylate monomer, and the difunctional (meth)acrylate monomer is included in an amount of less than 1% by weight based on the total amount of the resin composition. According to claim 1,
The resin composition further includes a phosphate ester-based (meth)acrylate monomer, and the phosphate ester-based (meth)acrylate monomer is included in an amount of 1 wt% or more and 10 wt% or less with respect to the total amount of the resin composition. According to claim 1,
The resin composition further includes an organic solvent, and the organic solvent is included in an amount of less than 1% by weight based on the total amount of the resin composition. It contains a urethane (meth)acrylate oligomer, and contains a polymer derived from a resin composition having a viscosity at 30°C or higher and 50°C or lower measured by the JIS Z8803 method of 20 mPa·s or less,
When a shear strain of 2000 Pa is applied,
The difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%,
An adhesive member having a shear strain of less than 2% after 30 seconds of removal of the shear strain. 12. The method of claim 11,
The resin composition is an adhesive member further comprising a bifunctional (meth) acrylate monomer or a phosphate ester-based (meth) acrylate monomer. 12. The method of claim 11,
An adhesive member having a shear strain of less than 20% after 5 seconds after the load. display panel;
a window disposed on the display panel; and
an adhesive member disposed between the display panel and the window; including,
The adhesive member is
Derived from a resin composition comprising a urethane (meth) acrylate oligomer,
When a shear deformation of 2000 Pa is applied to the adhesive member,
The difference between the shear strain after 5 seconds after loading and the shear strain after 300 seconds after loading is less than 5%,
A display device with a shear strain of less than 2% after 30 seconds of removal of the shear strain. 15. The method of claim 14,
The thickness of the adhesive member is 50 μm or more and 200 μm or less. 15. The method of claim 14,
Further comprising an input sensing unit disposed on the display panel,
The adhesive member is disposed between the display panel and the input sensing unit or between the input sensing unit and the window. 17. The method of claim 16,
The display panel includes a display element layer and an encapsulation layer disposed on the display element layer,
The input sensing unit is disposed directly on the encapsulation layer,
The adhesive member is disposed on the input sensing unit. 15. The method of claim 14,
The adhesive member is formed by providing the resin composition directly on one surface of the window or on one surface of the display panel, and UV curing the provided resin composition. 15. The method of claim 14,
A display device comprising at least one folding area, wherein a radius of curvature of the folding area is 5 mm or less. 15. The method of claim 14,
A light control layer disposed between the adhesive member and the window, and an optical adhesive layer disposed between the light control layer and the window,
The optical adhesive layer includes a polymer derived from the resin composition.

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